THEMIS GBO data and data products by THEMIS

THEMIS GBO data and data products. by THEMIS GBO team*. Presentation prepared by: S. B. Mende 1, H. U. Frey 1, E. Spanswick 2 1 Space Sciences Laboratory, University of California, Berkeley, CA 94720, USA 2 University of Calgary, 2500 University Drive N. W. , Calgary, Alberta T 2 N 1 N 4, Canada e-mail: mende@ssl. berkeley. edu THEMIS Prime Mission Review GBO − 1 Berkeley, November 19, 2009

THEMIS GBO Team University of California – Berkeley (UCB) • S. B. Mende – GBO science lead • H. U. Frey, S. Harris, W. Rachelson, R. Sterling • Provides ASI development, system engineering, GBO system fabrication and construction, data archive and dissemination University of Calgary • E. Donovan – Canadian science lead • E. Spanswick, B. Jackel, M. Greffen • Providing GBO system deployment in Canada, field management, data collection, development participation University of California – Los Angeles (UCLA) • C. T. Russell – magnetometer science lead • Develop and provide ground magnetometer for GBO / EPO University of Alberta • I. Mann – magnetometer scientist • Providing access to Canadian magnetometer network THEMIS Prime Mission Review GBO − 2 Berkeley, November 19, 2009

GBO Science Objective Central issue to THEMIS - Substorm onsets timing and location. Global images taken from high altitude satellites e. g. IMAGE FUV produced such images. How to do it (and better) without global auroral imaging? GBO shall monitor the auroral light and ionospheric currents across North America in order to localize the time, location, and evolution of the auroral manifestation of the substorm. Themis mission requirement relating to GBO: Determine substorm onset time and substorm meridian magnetic local time (MLT) using All Sky Imagers (one ASI per MLT hr) and Ground Magnetometer (two GMAG per MLT hr) with t_res<30 s and d. MLT<1° respectively, in an 8 hr geographic local time sector including the US. THEMIS Prime Mission Review GBO − 3 Berkeley, November 19, 2009

THEMIS GBO THEMIS Prime Mission Review GBO − 4 Berkeley, November 19, 2009

GBO Derived Requirements THEMIS Prime Mission Review GBO − 5 Berkeley, November 19, 2009

ASI Requirements REQUIREMENT SYSTEM DESIGN GB. ASI-1: FOV. The field of view of the ASI shall be greater than 170°, full angle. Compliance. Yes GB. ASI-2: Exposure Time. Shall have an exposure duration that is programmable with a maximum exposure duration of no less than 1 second. Compliance. Yes GB. ASI-3: Spectral Response. Within passband of 400 to 700 nm, shall provide detectable response when stimulated with a source radiance less than 10 k. Rayleigh, at maximum specified exposure duration. Compliance. Expect minimum sensitivity < 1 k. R (5: 1 SNR) GB. ASI-4: Spatial Resolution. Shall provide aurora Compliance. Raw ASI image has > 250 pixel onset localization with accuracy better than 100 km resolution per image diameter. Thumbnails have (d. MLT< 1°) 0. 5° binning. GB. ASI-5: Viewport. Shall have heated dome viewport Compliance. Yes GB. ASI-6: Cadence Shall have a programmable repetition interval, minimum interval of no less than 10 seconds Compliance. Have demonstrated cadence of 3 s appears to be feasible THEMIS Prime Mission Review GBO − 6 Berkeley, November 19, 2009

THEMIS GBO network 20 sites operational in 2007 21 sites operational since October 2008, incl. 3 relocations by U. Calgary THEMIS Prime Mission Review GBO − 7 Berkeley, November 19, 2009

THEMIS GBO history GBO Data Version History GBO install. . . Full GBO compliment installed. L 1 data produced 2007/01/01 2009/01/01 2008/01/01 Earlier imager data formats were recorded during testing in 2003 -2006. By early 2006, all installed imagers were recording the current L 1 data format. GBO magnetometers do not have data format revisions, L 1 data was recorded from installation. GBO Imager Metadata History Imager “skymaps” (pointing information) are updated once per imaging season and in response to changes in imager orientation due to building shifts, camera replacement/maintenance, etc. KUUJ Shift All skymaps created/valid 2007/01/01 FSMI shift 2008/01/01 All skymaps updated GILL Shift TALO initial skymap created KUUJ Shift TPAS Shift 2009/01/01 All skymaps updated All skymaps are available online at http: //themis-data. phys. ucalgary. ca/data/skymap/ and are used by themis software. THEMIS Prime Mission Review GBO − 8 Berkeley, November 19, 2009

GBO data products 1. 2. 3. ASI keograms along local magnetic meridian • Delivered daily jpeg-compressed (Level-0) • Reprocessed ½ year later with full resolution images (L 1) Geomagnetically mapped thumbnail images • Delivered daily square-root intensity compression (L 0) • 1024 pixels within +-8 o magnetic Latitude and ~+-12 o Longitude • 3 seconds temporal resolution, 8 -bits Full resolution images (L 1) • 256 x 256 pixels covering about 600 km radius around station • Delivered about ½ year later • 3 seconds temporal resolution • Full 16 bit intensity scale Geomagnetic field measured at 2 Hz (Level-2) Calibrated GMAG data (L 2) available at THEMIS and SPDF sites. THEMIS Pseudo AL index is routinely produced (L 1 product). Delivered daily from GBO-sites, short delay from additional networks (CHARISMA, UAF, Greenland) THEMIS Prime Mission Review GBO − 9 Berkeley, November 19, 2009

Data products on web page Overview plots Mosaics and Movies CDF-files for data download THEMIS Prime Mission Review GBO − 10 Berkeley, November 19, 2009

All-sky imager performance Monitor position and brightness of Polaris in Gillam (left) and Fort Yukon (right) Position shows when camera was moved Over 3 years decrease in response 3% (GILL) and 6% (FYKN) THEMIS Prime Mission Review GBO − 11 Berkeley, November 19, 2009

Publications and data access - So far >100 THEMIS-Publications in refereed journal (November 1, 2009) - 35% publications used GBO data - Note: Bow shock and MP studies rarely use any ground-based data (exception: THEMIS and Antarctic ground based data is used in Mende et al. (2009), J. Geophys. Res. , 114, A 00 C 23, doi: 10. 1029/2008 JA 013496. Data access and download through UCB-SSL web Site (to 11/01/09) http: //themis. ssl. berkeley. edu/data_processing_check/ground_data_mirrors/ Mag. : 421 distinct users view summary plots, ~400, 000 CDF file downloads ASI: 1146 distinct user view summary plots, ~226, 000 CDF file downloads Data access and download through U. Calgary site: http: //themis-data. phys. ucalgary. ca: 8080/data/imager/ [including test (<2006) data] http: //themis-data. phys. ucalgary. ca: 8080/data/fluxgate/ Virtual Observatory Access: http: //www. gaia-vxo. org/ - Data is ingesting nightly THEMIS Prime Mission Review GBO − 12 Berkeley, November 19, 2009

Back up slides THEMIS Prime Mission Review GBO − 13 Berkeley, November 19, 2009

ASI Specifications Imager: • • • Field of View: 170º full angle Spectral passband: 400 – 700 nm (with IR filter) Sensitivity: < 1 k. R (5: 1 S/N) Spatial resolution: 290 pixel diameter all-sky-image Exposure duration: programmable, 1 sec typical Cadence: 5 s demonstrated, 3 s appears feasible Enclosure: • • Operate in external ambient – 50º to +40ºC • Hermetically sealed unit w/ nitrogen purge – Dessicant used for field repair – Hermetically sealed electrical connectors • • Polycarbonate/acrylic dome Maintain internal temperature at 20º ± 10ºC – Requires about 150 W heating worst case Flexible mounting THEMIS Prime Mission Review GBO − 14 Berkeley, November 19, 2009

Mag Requirements & Specifications System Features GPS Receiver Antenna and Electronics Integrated into one package May be located >30 M from host (RS 422 signals) NTP compatible (1 msec time accuracy) Flxugate Magnetometer ± 72 Kn. T dynamic range @ 0. 01 n. T Resolution (~23 bits) Offset DAC system for 256 possible ranges per axis 2 Vectors per second data rate Low Power < 4 W Small Size 22 cm x 13 cm x 5 cm Ruggedized All Weather Sensor Design USB interface for data retrieval and firmware upload THEMIS Prime Mission Review GBO − 15 Berkeley, November 19, 2009